Bitcoin Core won’t ever discard reorged blocks, till they’re pruned (which occurs no matter whether or not the blocks are within the lively chain or not).
Just one chain is taken into account “lively” at a time although. The principles are:
- Solely contemplate totally legitimate chains (i.e. if a block accommodates an invalid signature or the rest unlawful, it’s ignored, along with all its descendants).
- Amongst these legitimate chains, solely the one whose tip has essentially the most accrued work (roughly equal to the sum of the difficulties within the chain) is taken into account.
- If there are a number of legitimate ideas of equal accrued work, the one whose final block was obtained first is taken into account lively.
All different chains are thought of inactive, but when they get prolonged, they might find yourself turning into lively once more.
